Magnetic Definition and 1000 Threads

  1. H

    Weight changes under strong, uniform magnetic fields?

    Has anyone ever looked for reversible weight changes while materials are subjected to uniform, strong magnetic fields, such as those involved in nuclear magnetic resonance imaging (MRI) or spectroscopy? I suspect no one ever has, for lack of a reason, and any such effects would have to be...
  2. R

    Solar PV:What happens to the lost energy?inductive recovery?

    Hi there, I am new in here, thanks for any reply. I took same title of a previous closed 3D by pranj5. As understood main part of the energy absorbed by PV panels goes in reflection and heat. The heat origins mainly in electrons that are excited but not enough to jump or they jump but they...
  3. N

    What is the derivation of the ABC magnetic field components?

    Can somebody please post the derivation of the ABC magnetic field components whose magnetic field components in the three cartesian directions(B1, B2, B3) are given by the following: B1=A*sin(z)+C*cos(y) B2=B*sin(x)+A*cos(z) B3=C*sin(y)+B*cos(x)
  4. R

    How do plasma particles interact with a magnetic field?

    How does plasma particles (ions, electrons, neutral particles as a whole) interact with an applied steady-state magnetic field? If you have plasma at atmospheric pressure ejected from a plasma torch in the z-axis direction (upwards/north), how will two permanent magnets, axially aligned N-S to...
  5. kolleamm

    Is neodymium naturally magnetic?

    Also does it make a better core for an electromagnet than iron does?
  6. A

    Changing electric field generating magnetic field

    I would very much appreciate a clarification on what is meant by a changing electric field in the context of statements such as 'a changing electric field creates a changing magnetic field'. My question is does the electric field actually need to reverse as a lot of examples show where two...
  7. E

    I Can a Magnetic Field Create Gravity?

    This has been noodling in the back of my mind ever since I read about the field strength in magnetars etc. Magnetic fields store energy. Magnetic fields in magnetars are inconceivably large (~10^11T). This inconceivably large magnetic field contains ~4x10^27J/m3 From that famous guy whose...
  8. C

    Ion craft using magnetic field instead of E-field

    Hello folks, I did some research and I know a charged particle in a coil magnetic field travels along the lines of the coil. My thoughts are having a vertical cylinder and having charged ions flow down. 1. How can I figure out how much velocity the charged ions would have. 2. Would it...
  9. G

    How to find true north not magnetic north?

    How to find true north vs magnetic north? Online information says magnetic north moves around as much as 2.5 degrees. Lots of information online about true north 1 place save 5 degrees off magnetic, another place says 10 to 12 degrees, another place 10 to 25 degree, another place 15 to 30...
  10. A

    Is today's exam question unsolvable? - Proton Motion in a Magnetic Field

    <Moderator's note: Moved from a technical forum and thus no template.> Hello all, Earlier today I had an electromagnetism exam, and it seems to me that this problem is unsolvable. There's just too little information given. A proton enters an uniform magnetic field. It's initial speed v is...
  11. S

    How Is Current Calculated in a Mass Spectrometer?

    Homework Statement A certain commercial mass spectrometer is used to separate uranium ions of mass 3.92 multiplied by 10-25 kg and charge 3.20 multiplied by 10-19 C from related species. The ions are accelerated through a potential difference of 100 kV and then pass into a uniform magnetic...
  12. S

    How to find the magnetic force on a current-carrying tube in a neon sign?

    1. The problem statement, all variables, and given/known data Assume the Earth’s magnetic field is 52.0 mT northward at 60.08 below the horizontal in Atlanta, Georgia. A tube in a neon sign stretches between two diagonally opposite corners of a shop window—which lies in a north-south vertical...
  13. S

    How Do You Calculate the Speed of a Rod in a Magnetic Field?

    Homework Statement A rod of mass 0.720 kg and radius 6.00 cm rests on two parallel rails that are d=12.0 cm apart and L=45.0 cm long. The rod carries a current of I=48.0 A in a direction that makes it rolls along the rails without slipping. A uniform magnetic field of magnitude 0.240 T is...
  14. S

    What is the Correct Way to Calculate Magnetic Force on an Electron or Proton?

    <Moderator's note: Moved from a technical forum and thus no template.> So there was this question An electron that has velocity (2*10^6 i +3*10^6 j)m/s moves through the uniform magnetic field (0.03 i - 0.15 j) T (a) Find the force on the electron due to the magnetic field. (b) Repeat your...
  15. thee qs

    Expression of radius and helical motion in a magnetic field

    Homework Statement charged particule reaches a uniform magnetic B field with a velocity V , and at angle theta with the magnetic field . What is the expression of the relation , expressed as a ratio, of the radius and helical step of the trajectory of the particule . a- 2pi/tan a b- 2pi...
  16. thee qs

    Magnetic moment and magnetic field and dot product

    Homework Statement a magnetic moment of U = 1 (i) + 2 (k) , surrounded by a magnetic uniform field of B= 3 (i) + 4 (j) - 1 (k) find the potential energy in mJ ? Homework Equations dot product of 2 vectors ( ui*bi)+(uj*bj)+(uk*bk) = or finding the module of both vector and doing AB...
  17. thee qs

    Radius of a particle's path in a B field and magentic momentum force

    ok so 1- the magnetic momentum is = to u in the k axis ( xyz - ijk ) and the magnetic field B = -A/z4 + Be^Cz) , also in the k axis orientation so the magnetic force F , that is applied on the magnetic momentum is given by 4 choices ; and as i can understnd it, 3 of them are...
  18. G

    Magnetic energy stored in a cylindrical conductor

    Homework Statement So I came across with following problem: > Consider a cylindrical conductor of infinite length and circular section of radius a and that is traversed by a stationary current I. What is the magnetic energy stored in the conductor. Homework Equations 3. The Attempt at a...
  19. L

    Which of these metals provide magnetic shielding?

    Homework Statement This a question from an olevel paper and the marking scheme says B I don't understand why Homework Equations None a theory question The Attempt at a Solution Aluminum and copper has less magnetic property while iron is good magnetic material. I cannot understand why the...
  20. Zaya Bell

    Magnetic Energy: How Does a Compass Needle Move?

    A long thin current-carrying conductor have a magnetic field around it in the direction according the RHR. If a compass needle was placed beside the wire it moves to point in the direction of the magnetic field. Now the current in the wire doesn't diminish and can still light a bulb in its way...
  21. E

    Direction of Magnetic Force on a Wire Moving Down a Slope with Current I?

    Homework Statement A wire with a current of I (flowing into the screen) moves down on a slope. What is the direction of the magnetic force acting on it? Homework EquationsThe Attempt at a Solution I have no Idea why the answer isn't horizontal, but rather opposing its velocity direction.
  22. Andres Padilla

    How to measure the magnetic field/ induced fem in a system

    Homework Statement Hello, this is like an experiment of engineering.It is called a induction stove. The system consists of a bycicle, where I am going to pedal. This will turn a disk that have 20 small magnets around its circuference. Once the disk starts to turn, it will produce a constant...
  23. G

    Magnetic field in the case of a thin magnetized cylinder

    Homework Statement Consider a cylinder of thickness a=1 mm and radius R = 1 cm that is uniformly magnetized across z axis being its magnetization M= 10^5 A./m. Calculate the bound currents on the cylinder and, doing convenient approximations, the B field on the axis of the cylinder for z=0...
  24. I

    Magnetic field created by a current carrying wire

    Hi, I studied the Maxwell laws and the Biot Savart law and I found something I cannot answer. If you have a finite wire carrying current (let say 5m long) and you want to determine the magnetic induction vector due to it at some point that has distance r from the wire, you have 2 options I...
  25. J

    Magnetic field and coplanar loops

    Homework Statement Homework EquationsThe Attempt at a Solution The current in the inner loop should flow in anticlockwise direction so as to resist the increase in flux of the external magnetic field . But how do I deal with the outer loop since there is smaller loop inside it ? I think...
  26. J

    Exploring the Effects of Magnetic Fields on Metal Boxes: What Happens Inside?

    Homework Statement Homework EquationsThe Attempt at a Solution I have honestly no idea about this concept . Book doesn't mention anything about this . This looks similar to Faraday cage in electrostatics . But I don't understand how this works in case of magnetic fields . Is this related to...
  27. J

    Magnetic field due to a solenoid

    Homework Statement Homework EquationsThe Attempt at a Solution I am having trouble interpreting the language of the problem statement . What does it mean that "half number of turns are wound " ? When the solenoid is cut , the length becomes 1/4th of the original and number of turns also...
  28. T

    Simple Question about the direction of magnetic induction

    Homework Statement There is a magnetic field B=0.02 Tesla and its direction is toward the plane (perpendicular to plane, shown by X X X X X - I'm not sure how to say this direction in English,sorry). we have a copper wire (uniform bar) perpendicular to magnetic field from south to north. we...
  29. F

    Find the magnetic field at the center

    Homework Statement A wire carrying current I=7A is shaped as half circle of radius R=0.2m.The magnetic field B(in μT) at the center is : A)11.0(k) B)7.9(k) C)9.4(k) D)6.3(k) E)4.0(-k) Homework Equations B=(μ0 I)/(2πR) The Attempt at a Solution B = (4π*10-7 *7)/(0.2*2*π) * 0.5 (Multiply by 1/2...
  30. F

    Find the magnetic field at a point

    Homework Statement Homework Equations B=(μ0*I)/(2πr) The Attempt at a Solution B2 = (4*4*10-7)/(2*0.1) = 8 μT B1 = (3*4*10-7)/(2*0.1) = 6μT Could I know how to determine the directions ?
  31. NateTheGreatt77

    What actually makes a magnetic field?

    I have tried looking this question up and I hope I am posting this question in the correct spot. I have read a little about photon clouds which surround electrons in a magnet but since I see myself as a very visual learner I think I am trying to think about this question as if something is...
  32. A

    Moving metal object in a magnetic field

    Let's say I have a bullet flying by a magnet, the magnet will attract the bullet and change its trajectory so it will turn slightly. Does that trajectory change take energy? If it does, where does it come from? The kinetic energy of the bullet?
  33. Dante Meira

    Magnetic repulsion between a permanent magnet and an air coil

    I would like to receive some input about this "equation" formulated by me, a=f(i), regarding a system with a permanent magnet and an air core coil acting as an electromagnet, as described in the image: I understand that the acceleration provided to the toy car will be a function of the...
  34. H

    Find induced current, magnetic force, work in inclined plane

    Homework Statement [IMG]http://[url=https://ibb.co/b3Emfo]https://preview.ibb.co/gLaEY8/20180527_055248.jpg[ A conducting bar slides down without friction on a pair of conducting rails separated by distance d. Connected to resistor R and there magnetic field B directed upward, perpendicular to...
  35. N

    Can a magnetic field create a force on non-magnetic object

    can we modify a single magnet in a way which creates force on non-magnetic object
  36. Osvaldo

    Understanding magnetic balance in AC induction motors

    I need to find out how calculate magnetic forces appearing in AC induction motor rotor when it is not magnetically centered inside the stator.
  37. S

    Moving a conducting rod in a magnetic field

    Homework Statement A small conducting rod of length l moves with a uniform velocity v in a uniform magnetic field B. Explain how the end Y becomes positively charged. Homework EquationsThe Attempt at a Solution I know the concept, a force will act on the conductor which will push the...
  38. maxelcat

    Force on a current currying wire in a magnetic field

    Homework Statement This is a multi choice question from last years aqa a level. We know a positive reading is produced on the scales indicating something is pushing down on the scales. Please see the picture. Homework Equations We know current direction, not B field. The Attempt at a...
  39. kolleamm

    Magnetic field of a circular electromagnet?

    I know that the poles of an electromagnet that is straight is at the ends but what if the metal core is an iron ring?
  40. T

    Total magnetic moment of hydrogen in weak magnetic field

    "Calculated the total magnetic moment of a hydrogen atom in the ground state in a weak magnetic field which arises from hyper fine splitting of the ground state. How many beams does hydrogen produce from a Stern-Gerlach analyzer with a weak magnetic field?" I've calculated the magnetic moments...
  41. A

    Understanding the Relationship Between Time and Magnetic Field Induction

    Homework Statement A magnetic field perpendicular to the plane of a wire loop is uniform in space but changes with time tin the region of the loop. If the induced emf in the loop increases linearly with time t, then the magnitude of the magnetic field must be proportional to: a)t^3 b)t^2...
  42. X

    I Measuring Magnetic Field in Rotating Frame

    Consider that we have a magnet and a magnetometer (a fluxgate magnetometer with a single coil), standing still as shown in fig 1. In fig 1, the magnetic field measured at the axis z1 of the magnetometer coil is B1. But if everything (magnet, magnetometer and the axes) was rotating together...
  43. W

    Phase relation between the electric & magnetic fields in a plasma

    Homework Statement So I have got the question below. I am asked to find the phase difference between the electric field and magnetic field of electromagnetic waves traveling in a plasma, using the electrical conductivity expression. Now I have found the frequency of the waves and I know that...
  44. G

    What is responsible for the structure of magnetic fields?

    Both the gravitational and electric fields associated with matter are centered on the matter itself. However, for a bar magnet, the magnetic field seems to be emanate from discrete loops, only part of which pass through the matter of the magnet. What causes a magnetic field to have this...
  45. J

    Magnetic field of a long curent carrying tube

    Homework Statement Homework EquationsThe Attempt at a Solution To calculate magnetic field at 1 and 3 current flowing through sections A and C can be assumed as if current is flowing in a long straight wire along the dotted line . Now since the current and distances are same for 1 and 3 , B1...
  46. H

    What is the Magnetic Field and Flux at Point O?

    Homework Statement [/B] There is lead XY shaped as straight wire. Next to it, circular lead with radius 0.10 m. They are in the same plane. XY to center of circle, O is 0.20 m. Curent flowing through XY is 15.7 AHomework EquationsThe Attempt at a Solution 1) find magnetic field (B) at O[/B]...
  47. S

    Force on a ferrous object in a saturating magnetic field

    If I understand it so far - a ferromagnetic object is attracted to a magnetic field ie towards the direction of most concentrated flux. So if there is no gradient there is no net force on the object. If the flux is so strong that the object magnetically saturates, then increases in flux will...
  48. Alettix

    Magnetic field decay in cylinder coaxial with solenoid

    Homework Statement For a medium of conductivity ##\sigma##: $$ \nabla^2 \vec{B} = \sigma \mu \mu_0 \frac{\partial \vec{B}}{\partial t} + \mu \mu_0 \epsilon \epsilon_0 \frac{\partial^2 \vec{B}}{\partial^2 t} $$ A long solenoid with ##r=b## has n turns per unit length of superconducting wire anc...
  49. K

    Solving Magnetic Torque Problems with Unit Vectors: Homework Help

    Homework Statement Homework Equations m=N*I*A T=m X B m = n(unit vector) *m The Attempt at a Solution To calculate m, I know it is just plugging in the information. Thus, m=0.8. Now, the question is computing the unit vector, which has me confused. Using the right hand rule, and going along...
  50. A

    Finding the relationship between magnetic momentum and angular momentum

    Homework Statement A cylinder with radius ##R## and height ##h## which has a distributed charge on its surface with density ##\sigma## spins over its axis with angular velocity ##\omega##. If the cylinder has a mass density ##\rho##, find the relationship between magnetic momentum and angular...
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